The present disclosure relates to an illumination system for endoscopic applications comprising at least one substantially monochromatic light source having a predefined central wavelength between 400 and 500 nm or between 500 and 550 nm, an optical transmission path adapted to guide light emanating from the light source to an endoscopic region of examination, and an optical band-rejection filter, wherein the illumination system is adapted to illuminate at least a part of the region of examination by generating autofluorescence in surrounding tissue, and the band-rejection filter is adapted to attenuate at least said light source wavelength to a viewer and wherein said light source is the single light source in the illumination system. A further embodiment relates to an endoscope for examining a body cavity comprising tissue, the endoscope comprising a source of light consisting of a substantially monochromatic light source having a predefined central wavelength between 400 and 550 nm, means for guiding light from the substantially monochromatic light source towards at least a part of the tissue, and at least one band-rejection filter adapted to attenuate at least said central wavelength, wherein the substantially monochromatic light source is configured to generate autofluorescence in the irradiated tissue such that the irradiated tissue is observable, and wherein the endoscope is configured to display at least a part of the irradiated tissue through said band-rejection filter. A system for photodynamic diagnosis and/or therapy of bladder cancer is further disclosed herein.La présente invention concerne un système déclairage pour des applications endoscopiques qui comprend au moins une source de lumière sensiblement monochromatique ayant une longueur donde centrale prédéfinie entre 400 et 500 nm ou entre 500 et 550 nm, un trajet de transmission optique conçu pour guider la lumière émanant de la source de lumière à une région endoscopique dexamen, et un filtre de re
